Belt grinder and attachment for grinding pipe ends

ABSTRACT

The invention relates to a belt grinder, preferably used in combination with an attachment for the grinding of, for example, pipe ends characterized by the fact that a number of contact rolls having varying diameters around which the continuous belt is fitted as needed are made available and a device for adjustment of the belt tension that mechanically optimizes the tension of the grinding belt independently of the diameter of the contact roll is provided.

The invention relates to a belt grinder, preferably used in combination with an attachment for the grinding of, for example, pipe ends. The invention facilitates the creation of a multi-functional belt grinder which is suitable for grinding several different diameters at varying angles. Such belt grinders are used in the manufacturing of, for example, railings, frame structures and other pipe structures as well as shop fittings.

Already well known are only such machines that have integrated motors, switches and other expensive components.

It is thus the objective of the present invention to provide a belt grinder or, as the case may be, an attachment that can be operated with a multitude of contact rolls with varying diameters. This poses a particular problem since the belt tension area has to be adjusted correspondingly.

This objective is achieved with a belt grinder device in accordance with claim 1.

Best modes are described in the dependent claims. In accordance with the invention a number of contact rolls with varying diameters are made available for a belt grinder that preferably is fitted with an attachment for grinding, for example, pipe ends but that also is suitable for other uses so that the continuous belt can be fitted as needed around said contact rolls and a device for adjustment of the belt tension is provided that mechanically optimizes the tension of the grinding belt independently of the diameter of the contact roll.

The mechanical optimization can, for example, occur if the device used for the adjustment of the belt tension is fitted with a pneumatic spring, one end of which is secured in place while the other end is movable in an elongated hole in the belt grinder.

In accordance with an alternative mode the device can also be fitted with a mechanical spring, such as, a coil spring for the adjustment of the belt tension.

Also preferable, is an eccentric part fitted onto the device used for adjustment of the belt tension that is operated from the exterior of the belt grinder housing.

An additional alternative mode of the device for adjustment of the belt tension is fitted with a threaded spindle that can be operated from the exterior of the belt grinder housing.

It is essential for the invention that a load force is achieved which will ensure optimization of the grinding belt tension.

The device for adjustment of the belt tension can also be fitted in an attachment that is used in combination with an otherwise structurally unchanged belt grinder. This arrangement can also be fitted with the above mentioned mode variations. In a special mode it is required that when the device for adjustment of the belt tension is fitted in the belt grinder the position of the driving disc of the grinding belt is changed correspondingly to the diameter of the contact roll while the distance between the contact role and contact disc remains constant. Also possible are combinations that allow adjustment of the belt tension by varying the distance to center of the contact role and contact disc while the driving disc is secured in place so that the device for adjustment of the belt tension can be moved into the attachment as explained above.

During grinding abrasive dust is carried to a collecting tank that preferably is filled with a cooling medium. The cooling medium may be water.

The housing of the belt grinder and that of the attachment are, preferably, mechanically fixed onto each other, for example, using screws.

Examples of the invention are described in further detail below with reference to the drawings. The figures show:

FIG. 1 a belt grinder, partially open, fitted with an attachment in accordance with the present invention;

FIG. 2 a belt grinder and an attachment in separated state;

FIG. 3 a detailed view of the attachment;

FIG. 4 further structural details between the coupling mechanism of the belt grinder and attachment;

FIG. 5 a perspective view of the attachment fitted to the belt grinder;

FIG. 6 a view of the belt tension mechanism in the attachment;

FIG. 7 further details of the belt tension mechanism;

FIG. 8 in segments (a), (b) and (c) the placement of the driver disc in correspondence with the diameter of the contact role;

FIG. 9 side view of the pneumatic spring that is movable in an elongated hole, viewed from a slightly forward leaning angle;

FIG. 10 side view of the pneumatic spring that is movable in an elongated hole, viewed from a slightly backward leaning angle;

FIG. 11 side view of the tensioned pneumatic spring in the anterior position of the elongated hole;

FIG. 12 inclined back side view of the flat plate placed on the side that has four elongated holes fitted with a cross recessed screw placed in the center of the device;

FIG. 13 inclined back side view of the flat plate placed on the side that has four elongated holes fitted with a cross recessed screw placed in the center of the device;

FIG. 14 schematic view of the motor placed in two different arrangements.

FIG. 1 shows a belt grinder 100 that basically is suitable for indoor industrial use under non-humid conditions for grinding, for example, steel, stainless steel and metals. A grinding belt is actuated by a motor 102 as can more easily be seen in FIG. 2. An adjusting mechanism 104 can move the grinding belt used into lateral position. A lever mechanism 106 tightens and loosens the grinding belt. The motor 102 thus drives a driving disc 108 around which the grinding belt, which is not shown in the drawing, is led along a horizontal grinding table 110 which may be either raised or lowered and around a contact disc 112 back to the driving disc 108.

In accordance with the invention this, in itself already, well known belt grinder is operated with an attachment 200 that is fixed to the belt grinder 100 using a mechanical fixing mechanism 224, preferably a simple screw connection. The longer grinding belt is correspondingly led up to the attachment 200 and adjusted and fixed to it in a manner described in further detail below. The contact role 206 can be moved using the height adjustment 202. An integrated collecting tank 204 that is filled with a cooling medium, such as water, collects the abrasive dust that results from grinding.

FIG. 3 shows a detailed view of the attachment 200. The contact role 206 can be released and replaced by another by opening the mechanical locking device 208. A corresponding fixation ensures a secure fit. A lock screw 210 permits the setting of the workpiece depth position stop, the rotational lever 212 controls the sideward movement by way of a cross slide. Feeding is controlled by the adjusting lever 214. The lever installation 216, 218 allows for the adjustment of the center height of the contact roll 206. Finally, a screw vice 220 holds the workpiece in place. A mechanism 222 adjusts the angle with a large 10° nick and a small 5° nick. Basically, nicks of any size between 30° and 90° can be set following the above steps or adjusted to any desirable setting. To connect the belt grinder and attachment the electrical voltage is first turned off at the main switch and all eye protection and knurled screws are dismantled if they are interfering. The grinding mat and abrasive dust collecting tank must also be removed.

FIG. 4 shows the belt grinder and the attachment held together by 4 bolts 224. The grinding belt may be removed and the desired contact role is inserted into a clamp. Then the new grinding belt is inserted and tightened.

FIG. 5 shows the position of the tipping settings 226 that must be adjusted before initial installation.

FIG. 6 shows details of the mechanism for adjusting the tension of the grinding belt on the belt grinder in accordance with the present invention. A pneumatic spring 130, one end 132 of which is secured in place while the other end is movable in an elongated hole in the belt grinder but that can still be secured in place is shown. Alternative modes are possible, for example, using a mechanical coil spring, an eccentric part or a threaded spindle.

FIG. 7 shows additional details, such as, the additional elongated hole 136 under the driving disc 108 that is used for adjustments. Additional elongated holes could be used as guides.

FIG. 8 with segments (a), (b) and (c) shows that despite the varying contact role 206 diameters and the immovable contact disc 112 the same grinding belt with optimal belt tension can be used by moving the driving disc 108 (such as into the elongated hole 136 shown in FIG. 7). In other words, the center distance between the contact role 206 and the contact disc 112 remains constant while the driving disc 108 can be correspondingly moved. When the position of the driving disc 108 has been chosen the belt tension is optimized using a mechanism for adjusting the tension of the grinding belt, as is described above.

The characteristics of the invention disclosed in the above description, in the drawings as well as in the claims could be significant for the implementation of the invention individually as well as in any combination. 

1. Belt grinder (100), preferably in combination with an attachment (200) for the grinding of, for example, pipe ends characterized by the fact that a number of contact rolls (206) with varying diameters are made available for a belt grinder so the continuous belt can be fitted as desired around said contact rolls (206) and a device for adjustment of the belt tension is provided that mechanically optimizes the tension of the grinding belt independently of the diameter of the contact roll (206).
 2. Belt grinder (100) in accordance with claim 1 characterized by the fact that the device for adjustment of the belt tension is fitted with a pneumatic spiral (130) one end (132) of which is secured in place while the other end (134) is displaceable in an elongated hole (136) in the belt grinder (100).
 3. Belt grinder (100) in accordance with claim 1 characterized by the fact that the device for adjustment of the belt tension is fitted with a mechanical spiral, such as, a coil spiral.
 4. Belt grinder (100) in accordance with one of claims 1 to 3 characterized by the fact that the device for adjustment of the belt tension is fitted with an eccentric part which is operated from the exterior of the belt grinder housing.
 5. Belt grinder (100) in accordance with one of claims 1 to 4 characterized by the fact that the device for adjustment of the belt tension is fitted with a threaded spindle which is operated from the exterior of the belt grinder housing.
 6. Attachment (200) for securing to a belt grinder (100) in accordance with one of claims 1 to 5 characterized by the fact that a collecting tank (204) that can be filled with a cooling medium collects the shavings.
 7. Attachment (200) for securing to the belt grinder (100) in accordance with one of claims 1 to 6 characterized by the fact that a device for attachment to the belt grinder (100) is fitted with a mechanical fixing device for the relative fixing of the belt grinder housing (100) and the attachment (200).
 8. Attachment (200), preferably used for the grinding of, for example, pipe ends in combination with a belt grinder (100) characterized by the fact that a number of contact rolls (206) with varying diameters are made available around which the continuous belt can be fitted as desired and by the fact that a device for adjustment of the belt tension is provided that mechanically optimizes the tension of the grinding belt independently of the diameter of the contact roll.
 9. Attachment (200) in accordance with claim 8 characterized by the fact that the device for adjustment of the belt tension is fitted with a pneumatic spring one end of which is secured in place while the other end is displaceable in an elongated hole in the attachment (200).
 10. Attachment (200) in accordance with claim 8 characterized by the fact that the device for adjustment of the belt tension is fitted with a mechanical spring, for example, a coil spring.
 11. Attachment (200) in accordance with claims 8 to 10 characterized by the fact that the device for adjustment of the belt tension has an eccentric part or a threaded spindle that is operated from the exterior of the belt grinder housing (100).
 12. Belt grinder (100) in accordance with one of claims 1 to 5 characterized by the fact that the correct lateral position of the grinding belt and thus the uniform grinding belt tension on the running surface of the grinding belt is adjustable using a threaded spindle (104) that is fitted in a link plate on a motor flange (114).
 13. Belt grinder (100) in accordance with claim 12 characterized by the fact that the motor flange (116) can be mounted in two positions and the threaded spindle (104) in one mode is positioned behind the motor (102) and in another mode in front of the motor (102) which permits mutually complementary adjustment possibilities.
 14. Belt grinder (100) in accordance with claim 13 characterized by the fact that the adjustment using the threaded spindle (104) in its position behind the motor (102) is realized by exerting pressure on the cover plate while the adjustment using the threaded spindle (104) in its position in front of the motor (102) is realized by pulling the cover plate to thereby extend the bandwidth of adjustment possibilities due to the eccentric part of the spiral. 